Dynamics of fast pattern formation in porous silicon by laser interference

Patterns are fabricated on 290 nm thick nanostructured porous silicon layers by phase-mask laser interference using single pulses of an excimer laser (193 nm, 20 ns pulse duration). The dynamics of pattern formation is studied by measuring in real time the intensity of the diffraction orders 0 and 1 at 633 nm. The results show that a transient pattern is formed upon melting at intensity maxima sites within a time 1-µs) upon melting induced by homogeneous beam exposure and related to the different scenario for releasing the heat from hot regions. The diffraction efficiency of the pattern is finally controlled by a combination of laser fluence and initial thickness of the nanostructured porous silicon layer and the present results open perspectives on heat release management upon laser exposure as well as have potential for alternative routes for switching applications.Postprint (published version

Omnichannel retailing: a tale of three sectors

Accelerated by the COVID-19 pandemic, the long-anticipated digital transformation of traditional retail has become the new reality. Retailers are responding to changes in consumers’ shopping behaviours and their demand for new interaction channels and touchpoints to shop at their convenience, regardless of time and location. Consequently, retailers are experiencing a change from single-channel models to multi-channel and omnichannel models. Omnichannel retailing demands integrated channel management and operation to improve customers’ shopping experiences. This study uses measures of channel integration levels from previous research to analyse channel integration among leading vendors in three top retailing sectors (clothing and apparel, home furniture and grocery) and expands the analysis by including indicators of digital transformation. The model includes 27 indicators related to channel integration and 9 indicators of digital transformation, and compares the results across sectors. By so doing, the study also aims to help establish values that may be used as target or reference values of channel integration and digitalization of retailers across sectors, irrespective of their size. The research methodology uses the ’mystery shopper’ technique and includes the collection of data about the 165 leading companies in these sectors in Spain

Repercusiones de la variabilidad de la edad de jubilación y de los salarios en la viabilidad financiera de un plan de pensiones de empleo

La empresa que decide crear un plan de pensiones del sistema de empleo en favor de sus trabajadores, partícipes del plan, adquiere un compromiso ineludible respecto al pago futuro de las prestaciones económicas que cubre el plan a los posibles beneficiarios. Por tanto, debe decidir qué modalidad de plan desea crear y fiar la prestación de jubilación que éste garantiza (plan de prestación definida). En este trabajo se analizan, a través de la simulación del modelo que lo representa, variables relevantes del mismo como el coste normal y la provisión matemática. Para este fin, se utilizan dos métodos habituales de valoración actuarial y se consideran, igualmente, diferentes escenarios a fin de comprobar cómo afecta la variabilidad de la edad de jubilación y de los salarios a la viabilidad financiera de este tipo de plan de pensiones. También se realiza un análisis de sensibilidad de estas variables ante modificaciones en algunos de los parámetros más significativos del modelo

Factors of global change affecting plants act at different levels of the ecological hierarchy

Plants and ecosystems worldwide are exposed to a wide range of chemical, physical, and biological factors of global change, many of which act concurrently. As bringing order to the array of factors is required in order to generate an enhanced understanding of simultaneous impacts, classification schemes have been developed. One such classification scheme is dedicated to capturing the different targets of global change factors along the ecological hierarchy. We build on this pioneering work, and refine the conceptual framework in several ways, focusing on plants and terrestrial systems: (i) we more strictly define the target level of the hierarchy, such that every factor typically has just one target level, and not many; (ii) we include effects above the level of the community, that is, there are effects also at the ecosystem scale that cannot be reduced to any level below this; (iii) we introduce the level of the landscape to capture certain land use change effects while abandoning the level below the individual. We discuss how effects can propagate along the levels of the ecological hierarchy, upwards and downwards, presenting opportunities for explaining non-additivity of effects of multiple factors. We hope that this updated conceptual framework will help inform the next generation of plant-focused global change experiments, specifically aimed at non-additivity of effects at the confluence of many factors

Effects of particle size in wasted bread flour properties

Producción CientíficaBread is wasted at different stages in the food value chain, mainly in industry and retail markets. Wastedbread can be milled into flour to be used in the elaboration of other food products. Milling can generateflours with different particle sizes that influence their properties. This study analysed the effect of particlesize (200, 500 and 1000lm) on the hydration, pasting and gel properties of flours elaborated with fourdifferent stale breads. Bread flours show a higher cold water absorption capacity and a lower oil absorp-tion capacity than wheat flour. No differences in water absorption properties after heating were observed.The viscosity curves of bread flours presented lower values than wheat flour curves, and the gels obtainedwere weaker. Bread flour properties were not influenced by different particle sizes. Therefore, a lessaggressive milling, with a lower energy cost, can generates flours with properties similar to finer flours.Junta de Castilla y León (project VA177P20)TRANSCOLAB FEDER-Interreg España-Portugal project (project 0612_TRANS_CO_LAB_2_P

Dynamics of laser induced metal nanoparticle and pattern formation

5 págs.; 4 figs.© 2015 AIP Publishing LLC. Discontinuous metal films are converted into either almost round, isolated, and randomly distributed nanoparticles (NPs) or fringed patterns of alternate non transformed film and NPs by exposure to single pulses (20 ns pulse duration and 193 nm wavelength) of homogeneous or modulated laser beam intensity. The dynamics of NPs and pattern formation is studied by measuring in real time the transmission and reflectivity of the sample upon homogeneous beam exposure and the intensity of the diffraction orders 0 and 1 in transmission configuration upon modulated beam exposure. The results show that laser irradiation induces melting of the metal either completely or at regions around intensity maxima sites for homogeneous and modulated beam exposure, respectively, within ≤10 ns. The aggregation and/or coalescence of the initially irregular metal nanostructures is triggered upon melting and continues after solidification (estimated to occur at ≤80 ns) for more than 1 μs. The present results demonstrate that real time transmission rather than reflectivity measurements is a valuable and easy-to-use tool for following the dynamics of NPs and pattern formation. They provide insights on the heat-driven processes occurring both in liquid and solid phases and allow controlling in-situ the process through the fluence. They also evidence that there is negligible lateral heat release in discontinuous films upon laser irradiation.R.J.P., T.K., and C.E.R., respectively, acknowledge the Grant No. JCI-2012_13034 from the Juan de la Cierva program, the support of DAAD, and CONACYT-Mexico postdoctoral fellowship No. 175641. The authors gratefully thank Professor P. Leiderer from University of Konstanz for his support and the Electron Microscopy Laboratory of CENIM for helping with the SEM observations.Peer Reviewe